In the popular movie Ex Machina (2015), a brilliant but sinister software entrepreneur, working at his remote estate, creates a line of glamorous artificial intelligences. He then invites one of his company’s most promising young programmers to engage his latest creation in a kind of emotional Turing test. Can she convince him that she has a mind and an inner life—a soul?

The experiment ends badly. The entrepreneur would have done better to invite Thomas Nagel. For more than forty years, since the publication of “What Is It Like to Be a Bat?”, perhaps the most frequently cited paper in recent philosophical history, Nagel has been one of America’s best-known philosophers of mind.1

“What Is It Like to Be a Bat?” may also be the most frequently rebutted paper in recent philosophical history. Yet Nagel has not retreated. On the contrary. He is in this short book determined to do battle with “materialist anti-Darwinism.” Whatever one’s view of his argument, one cannot help admiring this philosophical chevalier sans peur:

I would like to defend the untutored reaction of incredulity to the reductionist neo-Darwinian account of the origin and evolution of life. It is prima facie highly implausible that life as we know it is the result of a sequence of physical accidents, together with the mechanism of natural selection … it flies in the face of common sense.2

I am all in favor of skeptical outsiders twisting the tails of intellectual eminences, or at least trying to, but there is not much concrete engagement with Darwinism in Mind and Cosmos. Nagel mostly restricts himself to general statements about its scope and limits, such as:

[F]or a long time I have found the materialist account of how we and our fellow organisms came to exist hard to believe, including the standard version of how the evolutionary process works. The more details we learn about the chemical basis of life and the intricacy of the genetic code, the more unbelievable the standard historical account becomes.3

And:

[C]ontemporary research in molecular biology leaves open the possibility of legitimate doubts about a fully mechanistic account of the origin and evolution of life.4

The reasoning that led Nagel to these judgments is not presented in any detail; he is, as he admits, a layman in science. What is argued at length is the thesis that, if consciousness and morality can be explained on evolutionary grounds, then the philosophical views Nagel has championed cannot be true.

The standard names for these views are “realism,” “objectivism,” and sometimes “anti-reductionism.” The strategic leitmotif is “not merely.” Truth is not merely ultimate consensus or warranted belief. The good is not merely pleasure; the bad is not merely pain. Consciousness is not merely computation. The mind is not merely the brain. Value does not consist merely in the fact of being valued. Morality is not merely a product of natural selection.

On the contrary: mind, value, truth, good, and bad all have real, objective, observer-independent existence.

The world’s inventory is a chronic subject of philosophical controversy, its history too familiar to need recounting. A historical perspective on this and other perennial philosophical problems risks being disabling: can anyone now hope to contribute anything new or definitive to these debates? Perhaps not. The temptation to scratch certain philosophical itches remains overwhelming.

What, then, is real, objective, observer-independent existence? Who, if anyone, denies it to truth, value, or consciousness, and what do they mean by it? What would decide the question?

Would, for example, asserting that “bodies (including brains) are all there is” commit the speaker to denying that she herself, or anyone else, had a mind? No; it is obviously possible to believe in the existence of minds—or at least, to use the word “mind” in a fashion that is indistinguishable from the way it is used by those who assert its non-identity with the body—while maintaining that only bodies exist. This is hardly the same thing, of course. I can use the word “Apollo” as others do, without ever believing in the existence of Apollo. Likewise, few down-the-line Darwinists consider themselves disqualified from invoking morality and virtue, no matter how insistently they are informed by value realists that they have no right to.5 Clearly there is, notwithstanding the refinements of centuries of argument, still some verbal slippage somewhere, some failure to employ the crucial words in precisely the same sense.

Is there something faintly question-begging in Nagel’s “doubts about whether the reality of such features of our world as consciousness, intentionality, meaning, purpose, thought, and value can be accommodated in a universe consisting at the most basic level only of physical facts”?6 It sometimes seems as if no one on any side of the debate has any doubt about the reality of those features of the world, or even about the everyday usage of the terms. The question is how best to characterize them. Perhaps non-physical facts are necessary for that task, but what are non-physical facts? The only non-physical facts Nagel refers to are, “consciousness, intentionality, meaning.” It is odd that Nagel did not refer to obvious non-physical facts, for example, contracts, debts, historical claims, issues at law, arithmetic, and so on.

These facts—“mind, meaning, and value”—are “as fundamental as matter and space-time in an account of what there is.”7 Nagel’s repeated insistence that “something more” than physics and biology is needed to explain how there can be conscious beings—that non-physical facts make all the explanatory difference—prompts a skeptical question. Can one not imagine two different worlds, one in which belief prevails in the objective reality of mind, meaning, and value, and another in which the words are used in non-philosophical contexts for the same purposes as in the other, but whose inhabitants profess not to believe in their objective reality? Could not those two worlds have identical beliefs about cognitive psychology, neurophysiology, evolutionary biology, even ethics? How would we distinguish them?8

The same sort of stubbornly pragmatic question suggests itself when, in the course of explaining why everyone really does believe in the objectivity of truth, whether consciously or not, Nagel points out that, obviously, some things are true even if no one will ever know them to be true. It does seem obvious, until one begins to quibble.9

Non-Realist: What things?

Realist: We can’t know. That’s the point.

N-R: So how do we know that truths are not knowable?

R: Well, let’s see. Someday all intelligent life in the universe will die out. Agreed?

N-R: For the sake of argument, yes.

R: And whatever happens after that, no one will ever know, right?

N-R: Right.

R: QED!

N-R: What do you mean? It’s quite clear that the claim that some truths are unknowable and the claim that some unknowable propositions are true is not the same thing. What’s true that no one will ever know?

R: Why, everything that happens after consciousness disappears.

N-R: But events aren’t true. Only propositions are true.

R: Well, how about this: “The earth will fall into the sun in 5 billion years.”?

N-R: Yes, that’s true. But it’s not something no one will ever know. We know it.

R: But lots of other things that we’ll never know about will happen in 5 billion years. Sentences about them will be either true or false.

N-R: What things?

R: One would think that the argument is too general to need examples.

The non-realist’s quibble is that you cannot frame a true sentence about something of which you have no knowledge. What is at stake? What is really at stake?

The objectivity of value and the good also makes all the explanatory difference, according to Nagel, in this case to reasoning about morality. It is not merely to an agent’s interests or feelings or aesthetic sensibility that an appeal for unselfish benevolence must be directed but to the actual structure and weight of values in the case at hand.

A judgment that one should not impose serious harm on someone else for the sake of slight benefit to oneself, for example, is based on the recognition that the reason against imposing the harm is much stronger than the reason for pursuing the benefit, and that the fact that the harm would be suffered by someone else is not a reason to disregard it.10

Does not “actual,” again, beg the question? Are all genuine values intelligible to all reasoning beings? Is it inconceivable that some reasoning beings do not feel sympathy, are not equipped with motor neurons? Even Nazi ideologues were reasoning beings; can one imagine a demonstration that would convince one of them that the “actual structure and weight of the values” involved in not “harming” his victims exceeded the paramount values of racial purity and supremacy? And what of the Daleks, the Cylons, or the Borg? Consider this exchange (Star Date, 2479):

The Borg: We are Borg. You will be assimilated.

Capt. Jean-Luc Picard: No, please…

Borg: We are a higher life form.

Picard: I don’t doubt it. But I’d have to relinquish all the memories and attachments that constitute me… to die.

Borg: We are immortal.

Picard: I’m glad for you. But that’s not what we humans value the most.

Borg: With your limited minds, you are incapable of reasoning about value.

Picard: Well, yes, I can see why you would think so. But can’t you see my point of view?

Borg: What is “seeing your point of view”?

Picard: Um… it’s imagining the other person’s way of looking at things.

Borg: What is “imagining”?

Picard: …

Borg: Prepare to be assimilated.

Suddenly the Enterprise’s transporter beam locates Picard’s coordinates and beams him back. He remains human—no thanks to moral philosophy. And yet, if maintaining the integrity of Picard’s species-being were an observer-independent good, logically compelling respect for Picard’s fundamental life choices, shouldn’t that have been demonstrable to a super-intelligence like the Borg? On the other hand, surely it is possible to have a logically impeccable demonstration that something is the case and yet pursue, endorse, or champion its negation. The problem of akrasia is an example. The Borg might realize that what they are doing is wrong; they might simply not care.

Mind and Cosmos imports into the largest philosophical framework the defining preoccupation of Nagel’s career: the mind–body problem. The key to this problem is announced in the first sentence of “What Is It Like to Be a Bat?”: “Consciousness is what makes the mind–body problem really intractable.”11 The enigma of consciousness is also what makes materialist neo-Darwinism unsatisfactory. “What has to be explained is … the coming into existence of subjective individual points of view—a type of existence logically distinct from anything describable by the physical sciences alone.”12 Bats have a point of view, Nagel argued; anything does of which we can ask “how it is for the subject himself.”13

Does a rock, then, have a point of view? I’m just asking.

Among the more serious responses to “What Is It Like to Be a Bat?”, Owen Flanagan’s is particularly cogent.14 Flanagan points out the ambiguity of “know” in such claims as “we cannot know what it is like to be a bat.” We can, after all, with present and foreseeable technology, know practically everything about what it is like to be a bat—that is, what it is like to echolocate, to hang upside down, even to eat large quantities of insects. We can fully describe the neural mechanisms of a bat’s every perception and motion. We can predict any bat’s actions with, for practical purposes, perfect accuracy. All of which we are or will be able to do for fellow humans as well. (It is hardly clear, of course, that anything like this is possible even for the sake of argument.) We can know more about the consciousness and experiences of both bats and humans than the subjects themselves. All we cannot do is have (or “capture” or “grasp”) those experiences. We cannot, that is, be those subjects.

Subjectivity, inner experience, the first person point of view. These are not mysteries. Persons, Flanagan insists, are “uniquely causally well connected to their own experiences.” If one asks what makes their experiences their experiences, one hopes that Flanagan that would not respond that they are uniquely, causally, well-connected to them. Moreover:

there is no deep mystery as to why this special causal relation obtains. The organic integrity of individuals and the structure and function of individual nervous systems grounds each individual’s special relation to how things seem to him. John Dewey put it best: “Given that consciousness exists at all, there is no mystery in its being connected with what it is connected with.”15

Of course, if we substitute the word “light” for the word “consciousness” this becomes decidedly less impressive.

The failure of scientific analysis to enable the analyst to reproduce the first-person point of view is, for Nagel, the proof that a naturalistic (materialist, physicalist) account cannot possibly serve as a theory of everything. But this, Flanagan counters, is to misunderstand the ambitions of naturalism. Naturalism does not aspire to say everything that can be said (to “exhaust the analysis,” in Nagel’s terms) of mental phenomena; that would indeed require experiencing them. Instead it merely seeks the best possible characterization of them:

a rich phenomenology, a theory of how the phenomenology connects up with behavior, a theory about how conscious mental events taxonomized into many different classes of awareness figure in the overall economy of mental life, a theory of how mental life evolved, and thereby a theory of which features of mind are the result of direct selection and which features are free riders, and finally … a theory of how all the different kinds of mental events, conscious and unconscious, are realized in the nervous system.16

If wishes were horses, beggars would ride.

Nagel is right to reject reductionism; subjective experience is uncapturable. But this does not refute naturalism, which is simply the theory that every mental event, though experienced by a person, is realized in the brain.

Still, there are two very different claims at work here: whether naturalism is limited, and so inadequate in some sense, and whether it is false. As long as “realized in the brain” is given no content, the claim that every mental event is realized in the brain is about as persuasive as the claim that every mental event is realized in the liver.

In the background of arguments about the objectivity of truth and value, there is often nihilism. “If there is no God,” Fyodor Dostoevsky wrote, “everything is permitted.” Nowadays William Bennett, Roger Scruton, and many others issue equivalent warnings about relativism. Leszek Kolakowski, perhaps the most distinguished recent antagonist of modernity, admonished us that Dostoevsky’s (more precisely, Ivan Karamazov’s) apothegm is “valid not only as a moral rule but as an epistemological principle”; that the absence of philosophical foundations must ultimately entail “cognitive nihilism.”17 If reason cannot resolve conflicts among values or interpretations, then force must become the final arbiter of morality and truth.

Mind and Cosmos mostly avoids apocalyptic declarations of this sort, though there are occasional hints. “The evolutionary story,” we are cautioned, “leaves the authority of reason in a much weaker position. This is even more clearly true of our moral and other normative capacities. … Evolutionary naturalism implies that we shouldn’t take any of our convictions seriously.”18 In other writings, particularly when criticizing Richard Rorty, Nagel has assumed a more alarmed, even a censorious, tone.19

There is no resolving immemorial philosophical antagonisms; not on this occasion, at any rate. But for sportsmanship’s sake, and because I admire Rorty no less than I do Nagel, let me quote two passages from Contingency, Irony, and Solidarity, which together state the case against which Nagel has, throughout his career, resolutely set his face.

The first is epistemological:

We need to make a distinction between the claim that the world is out there and the claim that the truth is out there. To say that the world is out there, that it is not our creation, is to say, with common sense, that most things in space and time are the effects of causes that do not include human mental states. To say that truth is not out there is simply to say that where there are no sentences there is no truth, that sentences are elements of human languages, and that human languages are human creations.

Truth cannot be out there—cannot exist independently of the human mind—because sentences cannot so exist, or be out there. The world is out there, but descriptions of the world are not. Only descriptions of the world can be true or false. The world on its own—unaided by these describing activities of human beings—cannot.

The suggestion that truth, as well as the world, is out there is a legacy of an age in which the world was seen as the creation of a being who had a language of his own. If we cease to attempt to make sense of the idea of such a nonhuman language, we shall not be tempted to confuse the platitude that the world may cause us to be justified in believing a sentence true with the claim that the world splits itself up, on its own initiative, into sentence-shaped chunks.20

The second is political, and takes off from the celebrated passage in George Orwell’s 1984 in which Winston Smith, confused by O’Brien’s anti-realist dialectics, protests to his diary that “Truisms are true, hold on to that! … Freedom is the freedom to say that two plus two make four. If that is granted, all else follows.”21 The reader of Mind and Cosmos can practically hear Nagel enthusiastically exclaiming “Exactly!” Rorty, however, demurs:

Emphasizing these passages (and others like them) has led many commentators to conclude that Orwell teaches us to set our faces against all those sneaky intellectuals who try to tell us that truth is not “out there,” that what counts as a possible truth is a function of the vocabulary you use, and what counts as a truth is a function of the rest of your beliefs. Orwell has, in short, been read as a realist philosopher, a defender of common sense against its cultured, ironist despisers.

On this reading, the crucial opposition in Orwell’s thought is the standard metaphysical one between contrived appearance and naked reality. The latter is obscured by bad, untransparent prose and by bad, unnecessarily sophisticated theory. Once the dirt is rubbed off the windowpane, the truth about any moral or political situation will be clear. Only those who have allowed their own personality (and in particular their resentment, sadism, and hunger for power) to cloud their vision will fail to grasp the plain moral facts. One such plain moral fact is that it is better to be kind than to torture. Only such people will try to evade plain epistemological and metaphysical facts through sneaky philosophical maneuvers (e.g., a coherence theory of truth and a holistic philosophy of language—the devices I employed in Chapter 1 [i.e., the passage quoted above—G. S.]. Among such facts are that truth is “independent” of human minds and languages, and that gravitation is not “relative” to any human mode of thought.

For reasons already given, I do not think there are any plain moral facts out there in the world, nor any truths independent of language, nor any neutral ground on which to stand and argue that either torture or kindness are preferable to the other. … The kind of thing Orwell did [in 1984]—sensitizing an audience to cases of cruelty and humiliation which they had not noticed—is not usefully thought of as a matter of stripping away appearance and revealing reality. It is better thought of as a redescription …22

Two wise and humane philosophers, equally impassioned in defense of civilized values, yet firmly opposed to each other’s arguments. It is a spectacle of some intellectual pathos.

Though an exceptionally short book, Mind and Cosmos is nevertheless, in one respect, extraordinarily ambitious. Nagel proposes not merely a new explanation for the origin of life and consciousness, but a new type of explanation: “natural teleology.” If psychophysical reduction is implausible, as Nagel has always insisted, then no materialist neo-Darwinian explanation will ever be satisfactory. The apparent alternative, a theistic-intentional account (i.e., intelligent design by a divinity), does not appeal to Nagel. He simply lacks, he explains, any sense of the divine. His interest is in the territory between the two: a secular account that allows for the emergence of mind as mind.

On a teleological account, “in addition to the laws governing the behavior of the elements in every circumstance, there are also principles of self-organization or of the development of complexity over time that are not explained by those elemental laws.”23 That is to say, the “preferred transitions”—to mind and value—“have a higher probability in virtue of … temporally extended developments of which they form a potential part.” Complexity and self-organization are “an irreducible part of the natural order.”24 Or, in one of only two vivid or figurative phrases in Mind and Cosmos, evolution is “biased towards the marvelous.”25

This is, Nagel engagingly admits, “obscure,” and as noted earlier, he is “not confident … that it makes sense.” But it is undeniably imaginative. It yields a picture of (the book’s other striking phrase) “the universe gradually waking up and becoming aware of itself.”26

“What Is It Like to Be a Bat?” in Thomas Nagel, Mortal Questions (Cambridge: Cambridge University Press, 1979), 165–80. &larrhk;

If I believe that minds do not equal bodies, then it is not possible that I am using the word in a way that is indistinguishable from those who deny that this is so. I believe that minds do not equal bodies and say so on every conceivable occasion. You believe that minds do equal bodies and say so on every conceivable occasion. Pretty easy to tell us apart, I should think. The very idea of using words in a certain way is not very clear, of course, but even so… &larrhk;

Some readers may think that this paragraph does just that. To say that x has a fine mind would seem to commit one to saying that there is a fine mind that x has. This may in the end be trivial, but the argument of this paragraph is that there may be no distinguishing two views, one of which admits, the other denies, that there is a fine mind that x has. &larrhk;

If knowledge is justified true belief, we can know only finitely many truths, because we can hold only finitely many beliefs, or if it is possible to hold infinitely many beliefs, then we can justify only finitely many of them. But there are obviously infinitely many truths—at least one for every natural number. &larrhk;